High-speed machining tool

ABSTRACT

Object: A high speed machining component, which has been improved in wear resistance and lubricating properties, and a high speed dry machining method using the component are provided. Particularly, a high speed cutting tool and a high speed cutting method are provided. Means for solution: A halogen element is ion-implanted into a machining component having a cemented carbide as a base material, and the machining component is contacted with a workpiece at a speed of 150 m/min or higher, whereby the wear resistance and lubricating properties of the component can be improved. If the machining component has a Ti-containing coating layer, its wear resistance and lubricating properties can be improved similarly. The use of a cutting tool including such a component enables high speed dry cutting without a cutting oil. By bringing the machining component of the present invention into contact with the workpiece at a high speed, a self-lubricating film can be formed on a surface of contact of the component with the work material.

TECHNICAL FIELD

This invention relates to a component which is excellent in wearresistance, lubricating properties, and fracture resistance, and can beused for high speed machining applications. The invention also relatesto a machining tool including the component, and a high speed machiningmethod, especially, a dry cutting method, using the tool.

BACKGROUND ART

In recent years, a high machining speed has been demanded from theviewpoint of increased productivity, and high speed cutting has beendesired, for example, in the field of cutting. The range of targets forhigh speed cutting has been expanded, and there has been a demand forthe application of high speed cutting to high hardness materials such ashot forging dies after hardening by heat treatment, and die castingmolds.

With conventional cutting methods, cutting oils were used for promotinga lubricating action and cooling a cutting edge, and cutting oils wereneeded, particularly, in high speed cutting. However, the use of acutting oil may aggravate a work environment because of a foreign odor,dirt, and greasy fumes. In addition, treatment of a waste oil may posethe problem of environmental pollution, and cause the corrosion oftools. Thus, dry cutting using no cutting oil is desired and, for thispurpose, there is need for the development of a cutting tool having wearresistance, fracture resistance, lubricating properties, and heatresistance. Such a cutting tool should desirably have theabove-mentioned characteristics even in a high speed region.

As tools for dry cutting, there are reports on tools having highhardness coatings formed on hard materials for improved durability.Their examples include a high speed tool steel having a Ti—Al—N—C-basedcoating (see Japanese Patent Application Laid-Open No. 1999-300518), andcemented carbides having coating layers comprising constituents such asTiCN, TiAlN, SiC and Al₂O₃ (see Japanese Application Laid-Open No.2000-336489 and Japanese Patent Application Laid-Open No. 2001-293611).Methods such as CVD and PVD are used for the formation of these coatinglayers. An attempt has also been made to perform ion implantation ofelements such as Cl and S into tungsten carbide for increased wearresistance (see U.S. Pat. No. 5,038,645).

With the conventional methods of applying coatings to base materials,however, a coating layer, which comprises a different material from thebase material, is deposited, so that peeling is apt to occur between thecoating layer and the base material. To enhance adhesion, a method offorming a plurality of layers has been attempted, but involves acomplicated process. Furthermore, even when a coating layer of highhardness is formed, its toughness may be low and, depending on amaterial to be cut (namely, a work material), fracture may occur,resulting in an insufficient tool life. In addition, when the workmaterial is cut with the high hardness coating layer, swarf deposits onthe coating layer, thus presenting the problem that cutting resistancein a high speed region is not fully decreased. With ion implantation oftungsten carbide, wear resistance is improved in a medium speed region(for example, a cutting speed of up to 91 m/minute), but performanceobtained is inferior to that of coated tools.

Because of the above-described problems, the cutting speed of thecurrent steels is often set at a maximum of 150 to 200 m/min even withthe use of a cutting oil, and is often set at 100 /min or less in drycutting. Thus, dry cutting in a high speed region is difficult.

DISCLOSURE OF THE INVENTION

The present invention has been accomplished in light of theabove-described circumstances. It is an object of the invention toprovide a machining component, especially, a high speed cutting tool,improved in wear resistance, fracture resistance, lubricatingproperties, cutting resistance, and heat resistance in a high speedregion. It is another object of the invention to provide a high speedmachining method, especially a high speed dry cutting method, using themachining component of the present invention.

The present inventors have diligently conducted studies, and found thatwhen a halogen element is added to a surface layer of a machiningcomponent, and a workpiece is brought into contact with the so treatedmachining component at a high speed, characteristics, such as wearresistance and lubricating properties, are improved in accordance withthe oxidation promoting effect of the halogen element. This finding hasled to the accomplishment of the present invention. According to thepresent invention, the machining component and the workpiece aresubjected to friction at a high speed to cause an interface reaction,whereby the surface of the machining tool according to the presentinvention, because of its excellent lubricating properties, enables highspeed machining without using a lubricating oil.

The above advantages of the present invention are presumed to beascribed to a self-lubricating layer containing a Ti oxide phase and/ora Ti-containing compound oxide phase (however, the valence of Ti isgreater than 2, but less than 4). The present invention is alsocharacterized in that the self-lubricating film can be formed andregenerated in process during a machining process in a high speedregion.

That is, the gist of the present invention lies in a high speedmachining component having a hard material as a base material, andcontaining at least one element selected from the group consisting offluorine, chlorine, bromine and iodine, the concentration of the elementbeing in the range of 0.2 mol % to 10 mol % within 1 μm from the surfaceof the base material. The gist of the present invention also lies insuch a high speed machining component that if the high speed machiningcomponent has a coating layer containing Ti and C and/or N on theoutside of the base material, the high speed machining componentcontains at least one element selected from the group consisting offluorine, chlorine, bromine and iodine, the concentration of the elementbeing in the range of 0.2 mol % to 10 mol % within 1 μm from the surfaceof the coating layer. The at least one element selected from the groupconsisting of fluorine, chlorine, bromine and iodine, can be added byion implantation. The machining component of the present invention isbrought into contact with a workpiece at a speed of 150 m/min or higher,whereby the high speed machining component can be produced.

Further, the gist of the present invention also lies in the above highspeed machining component treated in such a manner as to be brought intocontact with a workpiece at a speed of 150 m/min or higher.

The gist of the present invention also lies in the above high speedmachining component further having a self-lubricating film on a surfacein contact with the workpiece. The self-lubricating film is formed bybringing the high speed machining component into contact with theworkpiece at a speed of 150 m/min or higher. A material containing Ti ona surface layer is named as the workpiece used for formation of theself-lubricating film. The self-lubricating film contains a Ti oxideand/or a Ti-containing compound oxide, the average valence of Ti in theoxide and/or the compound oxide is greater than 2, but less than 4, andif the amount of Ti in the self-lubricating film is calculated as TiO₂,the mass ratio expressed as (mass of the calculated TiO₂/mass of theself-lubricating film) is 5% or more.

The gist of the present invention also lies in a high speed machiningmethod using the above-mentioned machining component. It also lies in ahigh speed cutting tool including the above machining component. Withthe high speed cutting tool of the present invention, the wear widthV_(B) of a tool blank after cutting is performed under conditionsincluding a depth of cut of 1.0 mm, a feed rate of 0.1 mm/rev, a cuttingspeed of 400 m/min, and a cutting length of 500 m can be set at 70 μm orless. Moreover, cutting can be carried out at a cutting speed of 150m/min or higher without the use of a cutting oil.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a model drawing of a cutting step.

FIG. 2 shows the cutting speed dependence of a cutting resistanceresultant force in connection with an ion-implanted P10 tool, aTiN-coated P10 tool, and an untreated P30 tool.

FIG. 3 shows the cutting speed dependence of a feed force in connectionwith the ion-implanted P10 tool, the TiN-coated P10 tool, and theuntreated P30 tool.

FIG. 4 shows the cutting speed dependence of a coefficient of frictionin connections with the ion-implanted P10 tool.

FIG. 5 shows the results of a wear test of the ion-implanted P10 tool.

FIG. 6 shows the results of observation of sections of the ion-implantedP10 tool used in cutting of a Ti-deoxidized steel.

FIGS. 7(a) to 7(d) show the results of elemental analysis, by XMA, ofsections of the ion-implanted P10 tool used in cutting of theTi-deoxidized steel.

FIG. 8 shows the results of XPS which measured the surfaces of aTiN-coated tool (upper) and an ion-implanted TiN-coated tool (lower)after cutting.

FIG. 9 shows the results of selected area electron diffraction performedat 4 locations of the surface layer of an ion-implanted TiN-coated toolafter cutting.

FIG. 10 shows the results of a cutting test conducted on a TiCN-coatedtool implanted with ions and a TiCN-coated tool not implanted with ions.

FIG. 11 shows a tool flank wear width after cutting with the use of anion-implanted TiCN-coated tool. A cutting speed was set at 500 m/min,and a cutting length was set at 500 m or 1,000 m.

FIG. 12 shows sectional views of flank wear states after cutting underthe conditions of FIG. 11.

FIG. 13 shows the results of observation of flank and a tool section(inset) after a cutting test performed in connections with anion-implanted TiCN-coated tool, with a Ti-deoxidized steel as a workmaterial. The observation of the flank was made by a laser microscope,while the observation of the tool section was carried out by an opticalmicroscope. The upper part of the inset corresponds to a region of 26 mm(long)×60 mm (wide), and the lower part of the inset corresponds to 80μm (long)×100 μm (wide).

FIG. 14 shows the results of observation of a flank and a tool section(inset) after a cutting test performed in connection with anion-unimplanted TiCN-coated tool, with an Al-deoxidized steel as a workmaterial. The observation of the flank was made by a laser microscope,while the observation of the tool section was carried out by an opticalmicroscope. The upper part of the inset corresponds to a region of 26 mm(long)×60 mm (wide), and the lower part of the inset corresponds to 80μm (long)×100 μm (wide).

DETAILED DESCRIPTION

Hereinbelow, the present invention will be described in detail.

The base material of the high speed machining component according to thepresent invention can be selected, as appropriate, in accordance withthe material for a workpiece and the shape of the workpiece aftermachining, and is preferably a hard material. The hard material includescemented carbide tool materials, ceramics, and ultra-high pressuresintered compacts defined under JIS B 4053, and refer to sinteredmaterials harder than metallic materials produced by the melting method.For example, there can be used alloy tool steels, carbon tool steels,high speed tool steels, powdery high speed tool steels, cementedcarbides, cermets, ceramics, forging die steels, alloy tool steels forhot dies, alloy tool steels for cold dies, bearing steels, stainlesssteels, heat resisting steels, aluminum and its alloys, titanium and itsalloys, molybdenum and its alloys, and tungsten and its alloys.

The base material may be coated, or need not be coated. The material forthe coating layer is preferably a high hardness material such as amaterial containing Ti and C and/or N. For example, TiC, TiN, TiCN andTiAlCN are named. In any of these materials, part of Ti may besubstituted by other metallic element. Moreover, a plurality of coatinglayers may be stacked.

If the base material is not coated, at least one element selected fromthe group consisting of fluorine, chlorine, bromine and iodine is addedto the surface layer within 10 μm, preferably within 5 μm, morepreferably within 1 μm, from the surface of the base material. If thebase material is coated, at least one element selected from the groupconsisting of fluorine, chlorine, bromine and iodine is added to asurface layer within 10 μm, preferably within 5 μm, more preferablywithin 1 μm, from the surface of the coating layer. This element mayextend to the base material, without being confined in the coatinglayer. If the region where the element exists is too thin, durabilitydeteriorates, but if it is too thick, the step of implanting the elementis complicated.

The concentration of the fluorine, chlorine, bromine and iodine is 0.2mol % or higher, preferably 0.5 mol % or higher, more preferably 1 mol %or higher, but 20 or lower, preferably 10 mol % or lower, morepreferably 8 mol % or lower. If the concentration if too low,lubricating properties are difficult to improve. If the concentration istoo high, the crystal structure of the base material and/or the coatinglayer may be damaged. The concentration of the element within x μmrefers to the maximum element concentration in the range of the depth0-x μm when the distribution was measured by XPS, and the elementconcentration was plotted against the depth.

Ion implantation is named as the method of adding the fluorine,chlorine, bromine and iodine. Various publicly known apparatuses andconditions can be used in ion implantation, and the surfaceconcentration and energy of ion implantation can be selected, dependingon the base material and/or the coating layer, in order to fulfill theabove-mentioned surface layer concentration. For example, the surfaceconcentration is 1×10¹⁵ ions/cm² or higher, preferably 1×10¹⁶ ions/cm²or higher, but 1×10¹⁸ ions/cm² or lower, preferably 5×1¹⁷ ions/cm² orlower. Acceleration energy can be set at 20 keV or more, preferably 30keV or more, but 500 keV or less, preferably 200 keV or less.

An element other than those described above can be used instead of thoseelements or in combination with those elements, if this element is anelement which is incorporated into the surface layer of the machiningcomponent in the state where the element can contribute as an oxidizingagent during the machining step.

The base material may further contain Ti. The form of Ti is not limited,but its examples are titanium carbide, metallic Ti, titanium oxide, andtitanium nitride. It suffices that these Ti compounds are present atleast in the surface layer of the base material, and no restrictions areimposed on the Ti concentration, as long as it exerts no influence onthe characteristics of the base material. If the base material iscemented carbide, for example, the Ti concentration can be set at 0.2mol % or higher, preferably 1.0 mol % or higher, but 30 mol % or lower,preferably 15 mol % or lower.

If the machining component of the present invention does not have theTi-containing coating layer, it is preferred for the base material tocontain Ti. In this case, Ti can be rendered existent at the aboveconcentration in the surface layer ranging 20 μm, preferably 10 μm, morepreferably 1 μm, from the surface of the base material. If the Ticoncentration is too low, improvements in characteristics, such as wearresistance, lubricating properties and fracture resistance, may beinsufficient. If the Ti concentration is too high, the characteristicsof the base material, such as hardness and strength, may be impaired.However, Ti may be supplied from the outside by a method, such as thesue of a workpiece containing Ti. The Ti concentration is the surfacelayer ranging y μm from the surface references to the average Ticoncentration in the region with the y μm from the surface.

If the machining component has the coating layer, the Ti concentrationis 0.2 mol % or higher, preferably 1.0 mol % or higher, but 80 mol % orlower, preferably 60 mol % or lower, more preferably 30 mol % or lower,even more preferably 15 mol % or lower, in the surface layer ranging 20μm, preferably 10 μm, more preferably 1 μm, from the surface of thecomponent. The region where Ti is present at the above concentration maybe the Ti-containing coating layer.

Surface treatment for bringing the machining component, whichincorporates at least one element selected from the group consisting offluorine, chlorine, bromine and iodine, into contact with the workpieceat a high speed can improve the characteristics, such as wearresistance, fracture resistance, lubricating properties and heatresistance. The high speed refers to the relative speed of the machiningcomponent and the workpiece with respect to each other being 150 m/minor higher, preferably 200 m/min or higher, more preferably 250 m/min orhigher. There is no upper limit on the relative speed, but if it is 1000m/min or lower, the durability of the machining component is easy toretain. The surface treatment at this high speed can be performedwithout a lubricating oil.

If the machining component has no Ti-containing coating layer, the basematerial substantially does not contain Ti, and the workpiece free fromthe Ti is used, it is preferred to bring the machining component intocontact with a Ti-containing workpiece beforehand at a high speed (thistreatment will be hereinafter referred to as “high speed pretreatment”),thereby improving lubricating properties can be improved during themachining process, even without high speed pretreatment. However, notonly excellent characteristics can be obtained, beginning at a timeimmediately after the start of use of the machining component, but canthe characteristics such as lubricating properties be also optimized, bycarrying out the height speed pretreatment.

If the machining component has the Ti-containing coating layer, thelubricating properties can be improved during the machining processwithout the high speed pretreatment. By performing the high speedpretreatment, however, not only excellent characteristics can beobtained, beginning at a time immediately after start of use of themachining component, but can the characteristics such as lubricatingproperties be also optimized.

There are no restrictions on the workpiece, but if the workpiece is aTi-containing material such as a Ti-deoxidized steel, there is anadvantage for the improvement of the lubricating properties. Thepresence of Ti in the surface layer of the workpiece, in particular, inadvantageous for imparting the lubricating properties in high speedpretreatment and retaining the lubricating properties during themachining process.

If, after lubricating properties are imparted to the machiningcomponent, its surface of contact with the workpiece wears and itslubricity declines, the machining component is contacted again with aTi-containing workpiece at a high speed, whereby lubricating propertiescan be imparted. From the point of view of supplying Ti to the interfacereaction, it is preferred for the Ti-containing workpiece to contain Tiat least in its surface layer.

The reason why the wear resistance and the lubricating properties areimproved by the above treatment is not entirely clear. However, it isspeculated that a self-lubricating film formed on the surface of contactbetween the machining component and the workpiece may contribute tothese improvements. The self-lubricating film is not a coating layer(for example, the Ti-containing coating layer) adhered from the outsidebefore the machining component is put to machining applications, butrefers to a lubricating film formed by a reaction ascribed to themachining component itself. If the machining component has the coatinglayer, the self-lubricating film is formed on this coating layer. If themachining component has no coating layer, the self-lubricating film isformed on the base material.

The lubricating film formed by such a process, unlike the conventionalcoating layer, is advantageous in that is worn, it is regeneratedwhenever necessary, an d shows stable performance. Furthermore, the stepof forming the coating layer can be omitted, and the adhesion betweenthe protective layer and the base material can be enhanced. Besides, theself-lubricating film can suppress the deposition of the work materialon the surface of the machining component.

The thickness of the self-lubricating film is not limited as long as itenables the effects of the present invention to be exhibited, but thethickness is, for example, 0.05 μm or more, but 10 μm or less.

The constituent of the self-lubricating film is not limited, as long asit imparts wear resistance, lubricating properties, etc. However, if itcan undergo shearing deformation in accordance with a contact pressureexerted, lubricating properties can be improved. Thus, the constituenthaving such deformability is preferred. Examples of such a constituentare Ti oxides represented by TiO_(x) (1<x<2), various Mo oxides, Woxides, and Nb oxides. As the Ti oxide phase, a Magneli phaserepresented by Ti_(n)O_(2n−1) (n: integer) is named. A compound oxidecontaining one or more elements selected from the group consisting ofTi, Mo, W and Nb is also named. The compound oxide may contain Si and/orMn, and may, for example, be MnTiO₃. The self-lubricating film maycontain only one of the above phases, and may contain a plurality of thephases.

Ti of the self-lubricating film may be supplied from the machiningcomponent of the present invention, of may be supplied from the workmaterial. If the machining component has the coating layer, Ti can besupplied from the coating layer. If the machining component has nocoating layer, Ti can be supplied from the base material. If the Tioxide and/or the Ti compound oxide is contained in the self-lubricatingfilm, the average valence of Ti can be greater than 2, but less than 4.If the machining component has no Ti-containing coating layer, theproportion, in the self-lubricating film, of the amount of Ti in theself-lubricating film calculated as the mass of TiO₂ (hereinafterreferred to as the calculated TiO₂ mass), namely, the followingproportion

-   -   calculated TiO₂ mass/mass of the self-lubricating film×100 (%)        can be set at 5% or more, preferably 10% or more. If the        machining component has the Ti-containing coating layer, the        proportion of the calculated TiO₂ mass can be 10% or more,        preferably 20% or more, more preferably 40% or more. There is        not upper limit on the calculated TiO₂ mass, and the        self-lubricating film may be composed of a Ti compound alone.        However, the proportion of the calculated TiO₂ mass is often 90%        or less, for example, 80% or less, partly because an ingredient        derived from the work material may get in.

Herein, the value obtained as in Example 3 is used as the mass of theself-lubricating film. That is, W, Si, Nm, Al and Ti are measured byXPS, the sum of their masses is calculated on the assumption that theyare present as WC, SiO₂, MnO, Al₂O₃ and TiO₂, respectively, and thetotal value is taken as the mass of the self-lubricating film. Thecalculated TiO₂ mass refers to the mass of TiO₂ when all of Ti isassumed to be present as TiO₂.

The mechanism by which the self-lubricating film is formed by fractionat a high speed is not necessarily clear. However, there may be thefollowing situation: In an environment in which a high pressure load isimposed on the surface layer of the base material, for example, thehalogen element in the abase material is reduced into monovalentnegative ions. In accordance with this reduction, Ti is oxidized, withthe result that the aforementioned Ti intermediate oxide lay is formed.

The high speed machining in the present invention refers to machining ata relative speed, between the machining component and the workpiece, of150 m/min or higher, preferably 200 m/min or higher, more preferably 250m/min or higher. If the machining component of the present invention isused, dry machining (for example, dry cutting) can be performed withoutthe use of a lubricating oil.

The high speed machining component of the present invention can be suedfor any instrument, if it is applied to a site where friction occursupon contact between the machining component and the workpiece at a highspeed. For example, the machining component can be used for cuttingtools such as a drill, a milling cutter, a shaving cutter, a hob and anend mill, various molds such as hot forging dies and cold forging dies,and sliding components. If the machining component is used for a cuttingtool, the durability of the cutting tool can be improved to extend itslife, and its machining accuracy can also be improved.

With the cutting tool of the present invention, the self-lubricatingfilm is formed on the tool flank, so that wear is suppressed. Thereplacement or regrinding of the cutting tool is usually performed at atime when the flank wear width B_(B) of the tool reaches 200 to 300 μm,and V_(B) serves as a good indicator of the degree of wear. With thecutting tool of the present invention, the wear width when dry cuttingis performed under the conditions, a depth of cut of 1.0 mm, a feed rateof 0.1 mm/rev, a cutting speed of 400 m/min, and a cutting length of 500m, can be set at 70 μm or less, preferably 60 μm or less. In connectionwith the wear width V_(B) μm after dry cutting is performed under theconditions, a cutting speed of V m/min, and a cutting length of 500 m,the tool of the present invention can fulfill the conditions:

-   -   V_(B)≦V_(B0)+0.06375·V        where V is 100 m/min or more, but 500 m/min or less, and V_(B0)        is 30 μm. As noted here, the wear width B_(B) is suppressed even        at the high cutting speed V, so that the cutting tool can be        rendered long-lived. The dry cutting conditions for the        above-mentioned measurement of the wear width are as described        in Examples 1 and 5.

EXAMPLES

The present invention will be described in greater detail by thefollowing Examples, but the present invention is in no way restricted bythese Examples.

<Work Material>

Work materials used in the Examples are an Al-deoxidized steel and aTi-deoxidized steel. These steels were prepared by melt-forming a steelof the S45C composition by a 100 kg high frequency induction furnace,deoxidizing the product with Ti and Al when dividedly pouring it for 50kg steel ingots, hot rolling the steel ingots to ø75 mm, and normalizingthe hot rolled plates. The chemical compositions of the resulting steelsare as shown in Table1. The use of Ti for deoxidation is found toincrease the Ti concentration in the steel material. TABLE 1 Chemicalanalysis values of the work materials (mass %) Type of steel C Si Mn P SCu Ni Cr Mo S—Al T—N Ti O Ti- 0.44 0.34 0.80 0.002 0.001 <.01 <.01 <.01<.01 <.002 0.0009 0.0100 0.0011 deoxidized steel Al- 0.45 0.35 0.800.003 <.001 <.01 <.01 <.01 <.01 0.021 0.0006 0.0005 0.0006 deoxidizedsteel<Preparation of Cutting Tool>

An untreated P10 type-corresponding tool (composition: WC-TiC (TaC)30%-Co 10%, Sumitomo Electric Industries, Ltd., shape: TNUN331(triangular tip), model: ST10P), a TiN-coated P10 type-correspondingtool (P10 type-corresponding tool multi-layer-coated with TiCN, Al₂)₃,and TiN in this order, MITSUBISHI MATERIALS CORP., shape: comparable toP10 tool, model: UE6005), and a TiCN-coated P10 type-corresponding tool(P10 type-corresponding tool vapor-deposited alternatively withultra-thin films of TiC and ultra-thin films of TiN, Sumitomo ElectricIndustries, Ltd., shape: TNUN331, model: K29J) were ion-implanted usingchlorine. The conditions for the ion implantation were 100 keV and1>10¹⁷ ions/cm² for all of the tools. The ion implantation was performedonly for the rake face. The maximum chlorine concentration measured byXPS was 5 mol %.

The Ti concentration of the uncoated P10 type-corresponding tool was 23mol %, while the surface Ti concentration of the coated films were 1 to5 μm.

Example 1

Cutting Resistance Test of the Uncoated Tool

The ion-implanted P10 tool, and an ion-unimplanted TiN-coated P10 toolwere subjected to a dry cutting test in a low speed to a high speedregion to measure cutting resistance. As a control, a P30 tool (anuntreated product which has not been ion-implanted or coated,composition WC-TiC (TaC) 8%-Co 10%, MITSUBISHI MATERIALS CORP., shape:comparable to P10 tool, model: UT20T) was also subjected to the test.The cutting conditions were as follows:

-   -   Depth of cut Dc: 1.0 mm    -   Feed rate f: 0.1 mm/rev    -   Work materials: Al-deoxidized steel and Ti-deoxidized steel of        Table 1    -   Cutting speed: Increased from 10 m/min to 300 m/min with the        same tool

A force exerted on the tool during cutting, and the formation of aself-lubricating film are shown in FIG. 1.

FIG. 2 shows the cutting speed dependence of a cutting resistanceresultant force (R). All of the tools had maximum values in the mediumspeed region (40 to 100 m/min), and the values decreased as the speedbecame high. However, the ion-implanted tool showed a characteristicbehavior in the high speed region.

At 20 to 50 m/min, it is seen that the ion-implanted tool has a greatercutting resistance resultant force than that of the TiN-coated tool, andthe rate of tan increase in the resistance resultant force in accordancewith the increase in the speed was also greater. As the cutting speedwas further increased, however, the ion-implanted tool showed lower R.That is, it is found that the results in the high speed region aredifferent from the results in the medium speed region; in the high speedregion, the ion-implanted tool obtains higher lubricating tool at 300m/min decreased from the value of the TiN-coated tool by 12%.

A comparison between the P30 type-corresponding tool and the tool of thepresent invention shows that an advantageous effect is obtained in themedium speed range as well. At the cutting speed of 50 m/min or higher,R decreased by about 20% in the tool of the present invention ascompared with the P30 type tool.

A similar phenomenon was observed with a feed force (Fs; FIG. 3). At acutting speed of 300 m/min, the tool of the present invention was ableto reduce Fs by 10 to 15% in comparison with the TiN-coated tool. Evencompared with the P30 type-corresponding tool, the tool of the presentinvention was able to reduce Fs by about 25% at a cutting speed of 50m/min or higher. As noted from these results, according to the presentinvention, the machining force can be decreased markedly by implantingions into the base material, without applying a coating.

Moreover, regarding the friction coefficient on the tool-swarf contactsurface (μ: FIG. 4) geometrically calculated from the principal force(Fc) and the feed force (Fs), the ion-implanted tool showed excellentcharacteristics in the high speed region. In connection with thefriction coefficient at 300 m/min, for example, the value of theion-implanted tool decreased by 10% in comparison with the TiN-coatedtool, showing that the ion-implanted tool is excellent in wearresistance. Compared with the P30 type-corresponding tool, theion-implanted tool showed a decrease of about 10% in the frictioncoefficient at a cutting speed of 50 m/min or higher. As seen from theseresults, the friction coefficient on the tool-cutting contact surfacecan also be decreased by the present invention.

In the cutting test of the ion-implanted tool, the tow types of workmaterials with different Ti concentrations (i.e., Ti-deoxidized steeland Al-deoxidized steel) were used, and higher performance was obtainedfor the work material with a higher Ti content (Ti-deoxidized steel).These results show that if Ti is present in the work material, thelubricating properties of the cutting tool of the present invention arefurther improved.

Example 2

Wear Characteristics of Ion-Implanted Uncoated Tool

A wear test, by dry cutting, of the P10 ion-implanted tool wasconducted. The conditions for the test are as follows:

-   -   Cutting speed V: 50-250 m/min    -   Cutting length: 500 m    -   (Cutting time depends on the cutting speed: for example, it is        10 minutes at V=50 m/min, and 2 minutes at B=250 m/min)    -   Work materials: Al-deoxidized steel and Ti-deoxidized steel        described above

Other conditions were the same as those in Example 1.

The rake face wear depth (k_(T)) and flank wear width (V_(B)) of thetool after the test were measured to evaluate wear (FIG. 5). As shown inFIG. 5, when the Ti-deoxidized steel is used as the work material, k_(T)and V_(B) are smaller, and thus wear characteristics are improved.

Example 3

Analysis of Self-Lubricating Film of Ion-Implanted Uncoated Tool

In connection with the ion-implanted P10 tool used in the same cuttingas in Example 1, the resulting self-lubricating film was observed withan optical microscope (FIG. 6). As a result, the formation of the filmon the surface of contact with the work material was noted.

The composition of the film was measured by XAM (FIGS. 7(a) to 7(d). Asshown in FIGS. 7(a) to 7(d), Ti—Mn—Si compound oxides are formed in thevicinity of the surface of contact with the work material.

In FIGS. 7(a) to 7(d), W, Si, Mn, Al and Ti were measured in the filmregion, and their masses were calculated on the assumption that theywould exist as WC, SiO₂, MnO, Al₂O₃ and TiO₂, respectively, and the sumof these masses was taken as 100%. The values of the mass % obtained foreach compound based on this assumption were indicated for the respectiveelements in FIGS. 7(a) to 7(d). In regard to Ti, for example, the massration expressed as

-   -   TiO₂/(WC+SiO₂+MnO+Al₂O₃+TiO₂)×100 (%)        was indicated. Actually, however, W, Si, Mn, Al and Ti can exist        in different forms from WC, SiO₂, MnO, Al₂O₃ and TiO₂. The        indication (sSiO₂-bMnO-cTiO₂) in FIGS. 7(a) to 7(d) shows that        the Si/Mn/Ti molar ratio is roughly a/b/c.

Example 4

Analysis of Self-Lubricating Film of Ion-Implanted TiN-Coated Tool

Cutting was performed in the same manner as in Example 1 with the use ofthe ion-implanted TiN-Coated tool. Then, the elemental analysis of theself-lubricating film was make by XPS (FIG. 8), and the crystalstructure was examined by selected area electron diffraction (SAED)(FIGS. 9(a) to 9(d)). FIG. 8 also shows the results on anion-unimplanted TiN-coated tool as a control. The spectra in the upperpart and the lower part of FIG. 9 were measured by the same analyticaldevice under the same conditions, so that the peak absolute intensitiesof both spectra can be compared. On comparison of the peak intensitiesdue to Ti, the ion-implanted tool, a strong peak due to Fe is observed,suggesting that the work material is deposited on the surface layer. Inthe ion-implanted tool of the present invention, on the other hand,strong Ti peaks are observed, suggesting that the deposition of the workmaterial is suppressed, and a Ti-containing self-lubricating film isformed.

In FIG. 8, only the peaks of TiO₂ and TiN showed identity. However, thepeaks of Ti of Ti oxide and/or compound oxide phases having a Ti balanceof more than 2, but less than 4 are presumed to become shoulders on alower binding energy side than the peak of TiO₂. The presence of theseTi oxide phases is backed up by the electron diffractions of FIGS. 9(a)to 9(d).

FIGS. 9(a) to 9(d) also show the phases identified by the diffractionpatterns. Ti oxide phases (including a Magneli phase) having a Tivalence of greater than 2, but less than 4 are seen to have been formed.The results of FIGS. 9(a) to 9(d) show the formation of aself-lubricating film containing Ti oxide phases.

Example 5

Cutting Test of Ion-Implanted TiCN-Coated Tool

In connection with the ion-implanted TiCN-coated P10 tool, cutting wasperformed under conditions including a depth of cut (Dc) of 1.0 mm, afeed rate (f) of 0.1 mm/rev, and a cutting length of 500 m toinvestigate wear characteristics (FIG. 10). The aforementionedAl-deoxidized steel and Ti-deoxidized steel were used as work materials.For purposes of comparison, the test was also conducted on anion-unimplanted TiCN-coated tool.

When ion implantation was not performed, the wear width V_(B) sharplyincreased when the cutting speed exceeded 300 m/min, making cuttingdifficult at 500 m/min. With the ion-implanted tool of the presentinvention, on the other hand, cutting was possible even at the cuttingspeed of 500 m/min, showing that wear was suppressed. Particularly whenthe work material was the Ti-deoxidized steel, the increase in the wearwidth was slow even at the cutting speed of 300 m/min or higher, andV_(B) after cutting over a distance of 500 m at the cutting speed of 500m/min in the high speed region remained to be 57 μm. Even if thereplacement of the tool is to be carried out when V_(B=200) μm, it isexpected that cutting over 1,700 m or more can be performed.

FIG. 11 shows the relationship between the tool wear width V_(B) and thecutting length at a cutting speed of 500 m/min. When the work materialwas the Al-deoxidized steel, V_(B) increased nearly proportionately withthe increase in the cutting length. With the Ti-deoxidized steel, on theother hand, the increase in V_(B) was seen to slow when the cuttinglength exceeded 500 m. A comparison of the amount of increase in V_(B)between the cutting lengths of 500 m and 1,000 m shows that the value ofthe Ti-deoxidized steel was only ⅙ of the value of the Al-deoxidizedsteel.

As a cause of such a difference, a difference in the nature of theself-lubricating film formed on the tool flank is named. Theself-lubricating film corresponds to the region described as Belag inFIG. 12. When a Ti-containing material such as a Ti-deoxidized steel isused as the work material, it is speculated that a self-lubricating filmcontaining a Ti-containing oxide phase is formed, and effectivelyprotects the tool flank from rubbing against the machined surface.

In connection with the tool used in the cutting test of Example 5, thesurface of the flank was observed with a laser microscope, and a sectionof the tool was observed with an optical microscope.

FIG. 13 shows the results of observations with a laser microscope(scanning laser microscope, 1LM21W, Lasertec Corp.) and an opticalmicroscope after the above test was performed over a cutting length of500 m in connection with the ion-implanted TiCN-coated P10 tool, withthe Ti-deoxidized steel as a work material. An oblique surface generatedon the surface of the flank reflects a self-lubricating film formedduring cutting. A dark, dense area observed in the sectional view isconsidered to correspond to the self-lubricating film.

FIG. 14 shows the results of observations with the laser microscope andthe optical microscope after the above test was performed over a cuttinglength of 500 m in connections with the ion-unimplanted TiCN-coated P10tool, with the Al-deoxidized steel as a work material. In FIG. 14,unlike FIG. 13, the formation of a clear self-lubricating film was notobserved. These results suggest that the formation of a self-lubricatingfilm is promoted by ion-implanting a halogen and using a Ti-containingwork material.

INDUSTRIAL APPLICABILITY

According to the present invention, a high speed machining componentexcellent in wear resistance and lubricating properties can be obtainedby ion-implanting a halogen, and/or a Ti-containing coating layer, andfurther bringing the so treated product into contact with a workpiece ata high speed. High speed dr cutting can be performed by a cutting toolusing this component.

1. A high speed machining component having a hard material as a basematerial, and containing at least one element selected from the groupconsisting of fluorine, chlorine, bromine and iodine, a concentration ofthe element being in a range of 0.2 mol % to 10 mol % within 1 μm from asurface of the base material.
 2. A high speed machining component havinga hard material as a base material, having a coating layer containing Tiand C and/or N on an outside of the base material, and containing atleast one element selected from the group consisting of fluorine,chlorine, bromine and iodine, a concentration of the element being in arange of 0.2 mol % to 10 mol % within 1 μm from a surface of the coatinglayer.
 3. The component according to claim 2, wherein the coating layercontains one or more members selected from the group consisting of TiC,TiN, TiCN and TiAlCN.
 4. The component according to any one of claims 1to 3, wherein the at least one element selected from the groupconsisting of fluorine, chlorine, bromine and iodine has been added byion implantation.
 5. The component according to any one of claims 1 to4, wherein a concentration of Ti is in a range of 0.2 mol % to 80 mol %within 1 μm from a surface of machining component.
 6. The componentaccording to any one of claims 1 to 5, wherein the base material is acemented carbide.
 7. A high speed machining component produced bybringing the component according to any one of claims 1 to 6 intocontact with a workpiece at a speed of 150 m/min or higher.
 8. Thecomponent according to any one of claims 1 to 6, further having aself-lubricating film is a film formed by bringing the component intocontact with the workpiece at a speed of 150 m/min or higher.
 9. Thecomponent according to claim 8, wherein the self-lubricating film is afilm formed by bringing the component into contact with the workpiece ata speed of 150 m/min or higher.
 10. The component according to claim 9,wherein the workpiece used for formation of the self-lubricating filmcontains Ti in a surface layer thereof.
 11. The component according toany one of claims 8 to 10, wherein the self-lubricating film contains aTi oxide and/or a Ti-containing compound oxide; an average valence of Tiin the oxide and/or the compound oxide is greater than 2, but less than4; and if an amount of Ti in the self-lubricating film is calculated asTiO₂, a mass ratio expressed as (mass of the calculated TiO₂/mass of theself-lubricating film) is 5% or more.
 12. A high speed machining methodincluding a step of bringing the component according to any one ofclaims 1 to 11 into contact with an article at a relative speed of 150m/min or higher to machine the article.
 13. A high speed cutting toolincluding the component according to any one of claims 1 to
 11. 14. Thehigh speed cutting tool according to claim 13 or 14, wherein a wearwidth V_(B) of a tool flank after cutting is performed under conditionsincluding a depth of cut of 1.0 mm, a feed rate of 0.1 mm/rev, a cuttingspeed of 400 m/min, and a cutting length of 500 m is 70 μm or less. 15.A cutting method including a step of cutting an article by the cuttingtool according to claim 13 or 14 at a cutting speed of 150 m/min orhigher without use of a cutting oil.
 16. A method for producing a highspeed machining component, including a step of bringing the componentaccording to any one of claims 1 to 6 into contact with a workpiece at aspeed of 150 m/min or higher.